Gas and vapor heaters

ABSTRACT

A gas and vapor heater which is prefabricated at the shop in sections with the casing, refractory, coils and heaters all complete and unitized, whereby a plurality of such sections may be readily assembled together in the field with a minimum of welding and assembly time, and wherein each section has its heater coils disposed substantially horizontally and each section is of such a height that it can be readily transported by truck or rail to the field in the prefabricated condition.

United States Patent Inventor Hugo C. Mieth P. 0. Box 3152, Houston, Tex. 77001 Appl'. No. 879,047 Filed Nov. 24, 1969 Patented Sept. 28, 1971 GAS AND VAPOR HEATERS 3 Clallnl, 6 Drawing Figs.

US. Cl. 122/510 Int. Cl F221: 37/24 Field of Search 122/240, 1 275, 276, 279, 356, 510

References Cited UNITED STATES PATENTS 3,266,467 8/ 1966 Winship 122/510 3,272,186 9/1966 Lorenzini 122/336 3,530,835 9/1970 Wiesenthal 122/510 X 2,845,907 8/1958 Payne et al. 122/275 3,040,718 6/1962 Dwyer 122/356 3,066,656 12/1962 Hensel [22/240 3,453,087 7/1969 l-lcrp Jr., et al. 122/510 X Primary Examiner-Kenneth W. Spraque Attorney-Havel, Wilson & Matthews ABSTRACT: A gas and vapor heater which is prefabricated at the shop in sections with the casing, refractory, coils and heaters all complete and unitized, whereby a plurality of such sections may be readily assembled together in the field with a minimum of welding and assembly time, and wherein each section has its heater coils disposed substantially horizontally and each section is of such a height that it can be readily transported by truck orrail to the field in the prefabricated condition.

PMEmEu sirzsasn 3,608,528

' sum 3 OF 3 ATTORNEYS GAS AND VAPOR HEATERS BACKGROUND OF THE INVENTION The field of this invention is high temperature gas and vapor heaters.

Heretofore, high temperature low pressure drop gas and vapor heaters for commercial installations such as those called Ultraformers,"c Platformers" and steam'air super heaters have utilized a large number of small tubes arranged in vertical wickets, horseshoes or U-bends and attached to large diameter horizontal headers. Because of the height of such prior heaters, it was usually necessary to only partially form them in the shop so that the heaters could be transported to the field. Because of such prior vertical disposition of the heater tubes or coils, either the tubes themselves had to be cut off or only partially formed at the shop and then separately welded in the field or plant location to complete the construction of the heater, or where the coils were already welded when shipped, they had to be installed in the casing in the field. Such field operations have been expensive and time-consuming so that the installed cost of the prior heaters has been relatively high.

SUMMARY OF THE INVENTION The present invention relates to a high temperature low pressure drop gas and vapor heater which is essentially all shop prefabricated, regardless of the final height'of the installed heater in the field or at the plant location for use. Either the need for welding a multitude of heater tubes in the field or the installation of tubes in a casing in the field is eliminated, and instead, only a minimum of assembly and welding is necessary for the final installation of the heater of the present invention.

The heater is constructed with the heater tubes or coils substantially horizontally so that the length thereof is sufficient for heating purposes while still permitting each of the tubes to be completely prefabricated in the shop. The pressure drop of the heater is varied by combining sections as needed at the job site and with a minimum of welding and assembly time, and the capacity is generally regulated by the length of such sections. However, those two design considerations are inter related and may be varied by a person skilled in the art.

BRIEF DESCRIPTION OF THE DRAWING FIG. 1 is an elevation, partly in section, illustrating one form of the invention;

FIG. 2 is an end view, partly in section, of the apparatus of FIG. 1;

FIG. 3 is a view taken on line 3-3 of FIG. 2; FIG. 4 is a partial sectional view taken on lines 4-4 of FIG.

FIG. 5 is an elevation of a modified form of the invention, wherein a plurality of sections are shown separated from each other, and with certain parts removed; and

FIG. 6 is a view taken on line 6-6 of FIG. 5 and illustrates further details of the form of the invention illustrated in FIG. 5.

DESCRIPTION OF THE PREFERRED EMBODIMENTS In the drawings, the letter A designates generally the apparatus in the form illustrated in FIGS. 1-4. Such apparatus A is formed of one or more prefabricated sections S, two of which are illustrated in FIG. I. Each of the prefabricated heating sections S includes a plurality of heating coils or tubes T, each of which is disposed substantially horizontally and is of a substantially U-shape, with the ends connected to headers 10 and II, as will be more fully explained. The tubes T are disposed in a casing or housing 12 formed of steel or other material, and which is lined with a refractory material 14 of conventional construction. As will be explained, when a plurality of the heater sections S are to be assembled together in the field, each section S is prefabricated so as to be unitized in the shop, and then each section S is shipped by truck or rail or other means of transportation to the job site or field location for the installation of the section S together to form the vapor and gas heater A of this invention. The time for the welding and other assembly of the sections S together is minimized so as to minimize the cost of installation. Also, the height, length and width of each of the sections S may be controlled when the sections S are prefabricated in the shop so that they may be transported over the highways or otherwise shipped to the job site or field location in the unitized prefabricated section S.

Referring now in particular to FIGS. l-4, each of the sections S is formed in essentially the same manner and with essentially the same parts. Thus, each section S preferably includes a supporting framework for the outer skin or casing 12 which includes two or more side frame members 15, which are preferably steel l-beams. The framework also includes horizontally or laterally extending framework braces 16 which may be angle irons or pipes which are suitably welded to the substantially vertical l-beam framework members 15. The housing or casing 12 is also formed of steel or similar material which may be welded or otherwise joined to the framework composed of the side vertically extending members 15 and the horizontally extending braces 16. For the uppermost section S, horizontally extending upper framework beams or members 17 are preferably provided for joining together the members 15 and for otherwise unitizing the outer framework of the section S. For the section S which is the lowermost section in a particular apparatus or heater A, a plurality of interconnecting lower base members 18 (FIGS. 1 and 2) are preferably welded or are otherwise connected together with the side members 15. As will be more fully explained, the abutting ends of 15a of the members 15 are welded or are otherwise secured together in the field or at the job site.

Suitable refractory material either in cast form or as insulating firebrick is mounted in the casing or housing 12 in any conventional manner. For joining each of the sections S together in the field or at the job site, the casing or housing 12 for each of the sections S has a flange 12a which are adapted to be disposed adjacent to each other and which are provided with suitable bolt holes or openings for receiving bolts 19 and nuts 19a therewith. Instead of bolting the flanges 12a together, they may be welded or otherwise secured together. Where the refractory 14 of the sections S are disposed adjacent to each other, in proximity to the flanges 12a, a section of mineral wool 20 or other suitable insulating material is disposed at the time of the assembly in the field (FIG. 2).

To facilitate maintenance of the apparatus A after it has been installed, and to also provide an opening for the initial mounting and positioning of the heater tubes T, it is preferable to provide a removable end cover 25 which is formed essentially the same as the rest of the housing and refractory portion of the section S, except that it is formed at the end of the section S. Thus, the end cover 25 for each of the sections S includes curved or arcuate angle iron or reinforcing framework members 16' which are welded or are otherwise securedto the outer casing or housing 12' formed of steel or other similar material. Refractory material 14' is disposed inwardly of the casing or housing 12' in the same manner as described heretofore in connection with the casing 12 and the refractory 14. The end cover 25 is provided with longitudinally extending connecting flanges 25a which are adapted to abut with corresponding connecting flanges 25b on the main portion of the housing or casing 12. The flanges 25a and 251; are joined together by suitable connecting means such as bolts 26 having nuts 26a therewith. Each end cover 25 is preferably curved to conform substantially with the curved portions 30 of the tubes T (FIG. 3).

Each of the tubes T is formed with a bend or curved portion 30 in the form of the invention shown in FIGS. 1-3, although this may be varied as desired (see for example FIG. 6 to be hereinafter described). Each tube 30 is formed of steel or other metal and is suitably supported throughout its length at various points by steel or other support members 31 (FIGS. 3 and 4) which are connected to the framework members 15 with rivets 31a (FIG. 4) or other suitable connecting means. The supports or brackets 31 simply extend into the interior of the section S, and the tubes T rest thereon. One end 32 of each of the tubes T extends into the inlet header 10 (FIG. 3), and the other end 33 of each of the tubes T extends into the outlet header 11 (FIG. 1). The ends 32 and 33 of the tubes T are welded or are otherwise secured to the headers 10 and 11, respectively, and all of such welding is accomplished in the shop. Each of the headers 10 and 11 is of substantially the same height as the rest of the section S and the adjacent edges 11a of the header 11 are welded together at the place of installation (FIG. 1). The adjacent ends (not shown) of the header 10 for each of the sections S are likewise welded together at the place of installation.

To protect the headers 10 and 11, header covers 40 and 41 are provided for the headers 10 and 11, respectively. Such header covers 40 and 41 do not need to be welded in the field since they are separable from the rest of the heater A. The header covers 40 and 41 are suitably secured to the casing 12 or other parts of the framework with screws or bolts 40a and 410, respectively, or other suitable attaching means.

The heating means for the heater A preferably includes a plurality of gas burners 50 of any suitable construction, each of which is connected to a source of natural gas or other fuel capable of burning to produce a relatively high temperature within the interior of the heater A. The refractory walls 14 reflect heat to thereby utilize radiant heat within the apparatus A to develop the high temperatures for heating a gas or vapor which is passed through the tubes T from the inlet header 10 to the outlet header II.

It is preferable to provide a suitable exhaust stack 60 at the upper end of the assembled apparatus A, although such stack 60 is not essential to the apparatus A. The stack A is mounted or is otherwise disposed on the upper section S at the field location or job site by welding or by suitable bolts (not shown). A suitable dampener means 61 of any conventional construction is preferably incorporated in the stack 60 for regulating the discharge or exhaust of the gases from the heater A.

In the operation or use of the form of the heater A illustrated in FIGS. l-4, each of the sections S is prefabricated in the shop and is transported by truck, rail or other means to the job site or location for assembly. The stack 60 is preferably separately transported. In some instances, it may be possible to utilize only a single section S, but that determination will depend upon whether or not the height of the overall heater A is such that it can be carried or transported over the highways or on train cars.

Assuming the heater A is formed in a plurality of the sections S, the lowermost of the sections S is disposed at the desired site in the field or plant where it is to be located and assembled, and thereafter, the next sections S are mounted thereon in sequence, one above the other. The mounting is accomplished by the welding of the sections of the headers 10 and 11 together such as indicated at the weld between the ends 11a of the header 11 (FIG. 1). Also, the connection is effected by securing the bolts 19 and the nuts 19a through the connecting flanges 12a on the adjacent sections S. The stack 60 is welded or bolted to the uppermost section S as illustrated in FIGS. 1-3. An access opening with a cover plate 62 (FIG. 2) is preferably provided to permit a man to enter the interior of the heater A for inspection or maintenance. A pivoted door or window 63 of any suitable construction is mounted with the housing 12 so that it may be pivoted inwardly to permit a person to view the interior of the apparatus A while the unit is in operation. For maintenance purposes, the end cover 25 may be removed and thereafter replaced after the repair or other maintenance operations are performed within the interior of the heater A.

An alternate form of the invention is illustrated in FIG. 5, wherein the sections 8-1 are shown in an exploded relationship for purposes of illustration. Each of the sections 8-! has the same basic components as described heretofore in connection with FIGS. 1-4 and therefore like parts will bear like numerals, letters and other designations in both forms of the invention illustrated in the drawings. The heater tubes T-l illustrated in FIG. 6 of the drawings are modified in that the tubes T-l have longitudinal horizontally disposed sections 70 which are joined together by an end section 71, using ells 72 which are welded, threaded or are otherwise connected from the side sections 70 to the end section 71.

The sections 5-1 are identical in that they each have the same basic components as described heretofore in connection with the sections S. Thus, each is provided with a casing or housing 12 with a refractory liner internally thereof throughout the full inner wall of the heater section S1. The tubes T-l are welded or are otherwise connected to inlet and outlet headers (only header II is illustrated in FIG. 5). The outside framework for the housing or casing 12 is provided by any suitable supporting member such as the vertically extending members 15 and the horizontally extending braces 16. The adjacent sections 5-1 are bolted or are otherwise connected together by bolts extending through bolt holes 12b (FIG. 6) in connecting flanges 12a on the sections S1. The adjacent ends of the header 11 are welded together as described in connection with FIG. 1. Also, the adjacent edges of the other header 10 (not shown) are similarly welded together to form the final assembled heater. The number of the sections 5-1 which may be connected together is optional, depending upon the volume of gas or vapor flow to pass through the heater in the final assembled unit.

The form of the invention shown in FIGS. 5 and 6 has the same advantages as described heretofore in connection with FIGS. 1-4 in that each of the sections S-I may be of a height so that it may by transported by truck, trailer or other means of transportation over the highway, rails or other method of transportation. The sections 8-] are thus of a length, width and height for transportation without violating any of the legal limits for transportation over the highways and without disassembly for passing underneath the usual bridges and other similar highway obstructions. Since none of the tubes T or the tubes T-l must be welded in the field or at the job site, there is a minimum of welding and assembly time involved for putting the sections S and sections S-l together so that there is a minimum of expense in installing the heaters of this invention.

The foregoing disclosure and description of the invention are illustrative and explanatory thereof, and various changes in the size, shape, and materials as well as in the details of the illustrated construction may be made without departing from the spirit of the invention.

Iclaim:

1. A gas and vapor heater, comprising:

a plurality of prefabricated heater sections, each of such sections being shop fabricated and including:

1. a plurality of substantially horizontally disposed heating tubes, each of which is substantially U-shaped, and which are disposed at different elevations, one above the other, to form a vertical assembly of said tube;

2. a pair of substantially vertical headers having connection with the open ends ofeach of said heating tubes for circulating gas or vapor through said tubes;

3. a casing surrounding said vertical assembly of said tubes and having refractory material inwardly thereof to retain and reflect heat within the casing; and

4. heating means for supplying heat to the heater tubes within said casing;

means for mounting said sections together when mounted one above the other, said means for securing said sections together including welds for the adjacent edges of said headers.

2. The structure as set forth in claim 1 including connecting flanges on said sections adapted to contact each other when said sections are vertically mounted together and connection means holding said connecting flanges together.

3. A gas and vapor heater, comprising:

a plurality of prefabricated heater sections each of such sections being shop fabricated and including:

1. a plurality of substantially horizontally disposed heating tubes, each of which is substantially U-shaped, and which are disposed at different elevations, one above the other, to fonn a vertical assembly of said tube;

2. a pair of substantially vertical headers having connection with the open ends of each of said heating tubes for circulating gas or vapor through said tubes;

3. a casing surrounding said vertical assembly of said tubes and having refractory material inwardly thereof to retain and reflect heat within the casing; and

4, heating means for supplying heat to the heater tubes within said casing;

means for mounting said sections together, one above the other; and

means for securing said sections together when mounted one above the other;

a header box for each header, each of said header boxes being of substantially the same length as the plurality of vertically aligned headers of each section; and

means for releasably securing each header box to said sections. 

1. A gas and vapor heater, comprising: a plurality of prefabricated heater sections, each of such sections being shop fabricated and including:
 1. a plurality of substantially horizontally disposed heating tubes, each of which is substantially U-shaped, and which are disposed at different elevations, one above the other, to form a vertical assembly of said tube;
 2. a pair of substantially vertical headers having connection with the open ends of each of said heating tubes for circulating gas or vapor through said tubes;
 3. a casing surrounding said vertical assembly of said tubes and having refractory material inwardly thereof to retain and reflect heat within the casing; and
 4. heating means for supplying heat to the heater tubes within said casing; means for mounting said sections together, one above the other; and means for securing said sections together when mounted one above the other, said means for securing said sections together including welds for the adjacent edges of said headers.
 2. a pair of substantially vertical headers having connection with the open ends of each of said heating tubes for circulating gas or vapor through said tubes;
 2. The structure as set forth in claim 1 including connecting flanges on said sections adapted to contact each other when said sections are vertically mounted together and connection means holding said connecting flanges together.
 2. a pair of substantially vertical headers having connection with the open ends of each of said heating tubes for circulating gas or vapor through said tubes;
 3. a casing surrounding said vertical assembly of said tubes and having refractory material inwardly thereof to retain and reflect heat within the casing; and
 3. A gas and vapor heater, comprising: a plurality of prefabricated heater sections each of such sections being shop fabricated and including:
 3. a casing surrounding said vertical assembly of said tubes and having refractory material inwardly thereof to retain and reflect heat within the casing; and
 4. heating means for supplying heat to the heater tubes within said casing; means for mounting said sections together, one above the other; and means for securing said sections together when mounted one above the other, said means for securing said sections together including welds for the adjacent edges of said headers.
 4. heating means for supplying heat to the heater tubes within said casing; means for mounting said sections together, one above the other; and means for securing said sections together when mounted one above the other; a header box for each header, each of said header boxes being of substantially the same length as the plurality of vertically aligned headers of each section; and means for releasably securing each header box to said sections. 